Neutral polychloro-aliphatic acid esters of polyhydroxyphenols



nited States Patent NEUTRAL POLYCHLORO-ALIPHATIC ACID ESTERS OFPOLYHYDROXYPHENOLS Herman 0. Senkbeil and Harry F. Brust, Midland,Mich., assignors to The Dow Chemical Company, Midland, Mich, acorporation of Delaware No Drawing. Application October 12, 1956, SerialNo. 615,722

6 Claims. (Cl. 260-479) This invention relates to the neutral esters ofthe polyhydroxyphenols and the polychloro-aliphatic monocarboxylic acidssuch as the u,a-dichloro-aliphatic acids and u,u,B-trichloro-aliphaticacids containing from 3 to carbon atoms, inclusive, and trichloroaceticacid. These fully esterified polyhydroxyphenols or neutral esters areviscous liquids or crystalline solids somewhat soluble in many organicsolvents and of low solubility in water. They have been found to beactive as plant growth control materials and are adapted to be employedas active toxic constituents in dust and liquid compositions for thecontrol of the growth and killing of Weeds and for the sterilization ofsoil with regard to plant growth. They are also useful as parasiticidesfor the control of many insect, fungal and bacterial organisms'such asAlternaria solani and Panagrellus silusae.

The new compounds may be prepared by reacting together 1) apolyhydroxyphenol and (2) a polychlorolower aliphatic-monocarboxylicacid anhydride having the formula wherein R represents ana,u-dichloroacyl or a p-trichloroacyl radical containing from 3 to 5carbon atoms, inclusive, or trichloroacetyl. Suitable polyhydroxyphenolsinclude pyrocatechol, hydroquinone, resorcinol, pyrogallol,1,2,4,5-benzene tetrol, tetrachlorohydroquinone, 4,6-dichlororesorcinoland 4-chloropyrocatecho1.

The reaction takes place smoothly at the temperature range of from 90 to180 C. with the production of the desired neutral ester andpolychloro-lower aliphatic acid of reaction. Good results are obtainedwhen one molecular proportion of the polyhydroxyphenol is reacted withan amount of the polychloro-lower aliphatic acid anhydride equal inmoles to at least the number of hydroxyl units in the employedpolyhydroxyphenol. A large excess of the acid anhydride may be employedin the reaction mixture since such excess does not appreciably affectthe course of the reaction. The removal from the reaction zone of thepolychloro-lower aliphatic-monocarboxylic acid of reaction as formedgenerally results in optimum yields of the desired ester products.

In carrying out the reaction, the polyhydroxyphenol orchloro-polyhydroxyphenol and polychloro-lower aliphatic-monocarboxylicacid anhydride are mixed together and the resulting mixture heated at atemperature of from 90l80 C. for a period of time to complete thereaction. The heating may be carried out under reduced pressure and at atemperature at which the polychlorolower aliphatic acid of reactionboils to efiect the removal of by-product polychloro-loweraliphatic-monocarboxylic acid as formed. Upon completion of thereaction, the desired product may be separated by fractionaldistillation under reduced pressure. When the desired product Example1.Pyrocatechol bis-(a,a,;8-trichloropropionate) O-C-CC12CH2C1 A mixtureof 27.5 grams (0.25 mole) of pyrocatechol and 182 grams (0.54 mole) ofa,a,;9-trichloropropionic anhydride was heated with stirring at atemperature of from 111 to 138 C. and at a reduced pressure of 5millimeters for about 5 hours. The heating was carried out with thecontinuous distillation of the a,a,}8-trichloropropionic acid ofreaction as formed and until no further substantial amounts of acid wereliberated. The reaction mixture was then heated at temperaturesgradually increasing up to 187 C. at 5 millimeters pressure to removelow boiling constituents and obtain a pyrocatecholbis-(a,a,;3-trichloropropionate) product as a viscous liquid residue.This product had a chlorine content of 48.2 percent compared to thecalculated value of 49.65 percent.

Example 2.Pyr0catech0l bis-(a,a-dichl0r0propionate) 27.5 grams (0.25mole) of pyrocatechol and 170 grams (0.634 mole) ofa,a-dichloropropionic anhydride were mixed and heated with stirring at atemperature of from 98 to C. and at a reduced pressure of 10 millimetersfor a period of 15 hours. The heating was carried out with thecontinuous distillation of a,a-dichloropropi onic acid as formed anduntil no further substantial amounts of acid were liberated. Thereaction mixture was then fractionally distilled under reduced pressureto separate a pyrocatechol bis-(a,a-dichloropropionate) product as aviscous liquid boiling at 123-129 C. at 0.08 millimeter pressure. Thisproduct contained 39.5

percent chlorine compared to the calculated value of 39.40 percent.

Example 3.-Resorcin0l bis-(men-dichloropropionate) Resorcinol (27.5grams, 0.25 mole) was mixed with 174.2 grams (0.65 mole) ofa,u-dichloropropionic anhydride and the resulting mixture heated withstirring at a temperature of 150 C. for a period of 16 hours. Followingthe heating period, the reaction mixture was fractionally distilledunder reduced pressure to separate a resorcinolbis-(a,u-dichloropropionate) product as a viscous liquid boiling at143-l44 C. at 0.7 millimeter pressure and having a refractive index n/Dof 1.5185 at 25 C.

Patented Dec. 3, 1957 Example 4.-Tetrachlorohydroquinonebis-(a,a-dichloraprapionate) A mixture of 62 grams (0.25 mole) oftetrachlorohydroquinone and 141 grams (0.52 mole) ofa,a-dichloropropionic anhydride was heated with stirring for a period ofabout 16 hours and at a temperature of from 168 C. to 175 C. After theheating period, the reaction mixture was cooled to precipitate atetrachlorohydroquinine bis-(a,a-dichloropropionate) product as a whitesolid having a melting point of 24925 1 C. and a chlorine content of56.2 percent compared to the calculated value of 56.98 percent.

Example .3,6dichl0ro-1 ,2,4,5 -benzenetetrol tetra-(a,a-dichlor0pr0pionate) H3C-ClzC-fil-O O-C-CCh-CH:

A mixture of 29.6 grams (0.14 mole) of 3,6-dichlorol,2,4,5-benzenetetroland 166.2 grams (0.62 mole) of a,a-dichloropropionic anhydride washeated with stirring at a temperature of from 135 to 162 C. for a periodof 4.5 hours. The reaction mixture was then cooled to 60 C. and pouredinto methanol to precipitate the desired ester product as a whitecrystalline soli-d. This product was separated by filtration, dried andfound to melt at 202-205 C. and to have achlorine content of 50.6percent compared to the calculated value of 49.87 percent.

This compound is prepared in a manner similar to that described inExample 2 by heating a mixture of 0.33 mole of pyrogallol and 1.0 moleof u,a-dichlorobutyric anhydride. The a,ot-dichlorobutyric acid formedas a byproduct is removed by distillation during the heating period andthe residue thereafter fractionally distilled under reduced pressure toseparate a pyrogallol tIis-(a,a-dichlorobutyrate) product as a viscousliquid having a molecular weight of 543.

Example 7.4-chl0r0resorcin0l bis-(trichloroacetate) A mixture consistingof one mole of 4-chlororesorcinol and two moles of trichloroaceticanhydride is heated at about 150 C. and under a reduced pressure of 10millimeters while continuously removing the trichloroacetic acid ofreaction. Following the heating period, the reaction mixture isfractionally distilled under reduced pressure to separate a4-chlororesorcinol bis-(trichloroacetate) product as a colorless viscousliquid having a molecular weight of 435.

In a similar manner other fully esterified polyhydroxyphenols may beprepared as follows:

2,3-dichlorohydroquinone bis-(a,a-dichlorovalerate) by the reaction ofone mole of 2,3-dichlorohydroquinone and at least two moles ofa,a-dichlorovaleric anhydride.

3 ,S-dichloropyrocatechol bisa,a,/3-trichlor0butyrate) by the reactionof one mole of 3,5-dichloropyrocatechol and at least two moles ofoc,oz,]3triChl0I0bUtyrlC anhydride.

4,5,6-trichloropyrogallol tris-(a,a-dichloropr0pionate) by the reactionof one mole of 4,5,6-trichloropyrogallol and at least three moles ofa,a-dichloropropionic anhydride.

Tetrochlororesorcinol bis-(a,a,fl-trichloropropionate) by the reactionof one mole of tetrachlororesorcinol and at least two moles ofa,a,;8-trichloropropionic anhydride.

Hydroquinone bis-(a,a, 8-trichlorovalerate) by the reaction of one moleof hydroquinone and at least two moles of a,a,fi-trichlorovalericanhydride.

Pyrogallol tris-(a,a-dichloropropionate) by the reaction of one mole ofpyrogallol and at least three moles 11,1:- dichloropropionic anhydride.

Resorcinol bis-(a,u-dichlorobutyrate) by the reaction of one mole ofresorcinol and at least two moles of caudichlorobutyric anhydride.

The neutral esters of the present invention are effective as herbicidesfor the killing of weeds and the sterilization of soil with regard toplant growth. They are also valuable as parasiticides and are adapted tobe employed for the control of insect and fungal organisms such asAlternaria solani. For such use the products may be dispersed on aninert finely divided solid and employed as dusts. Such mixtures may alsobe dispersed in water with or without the aid of a wetting agent and theresulting aqueous suspensions employed as sprays. In other procedures,the products may be employed as active toxic constituents inoil-in-water emulsions or aqueous dispersions with or without theaddition of wetting, dispersing or emulsifying agents. In representativeoperations, percent controls of the growth of the seeds and emergingseedlings of oats and canary grass have been obtained with resorcinolbis-(a,ot-dichloropropionate) when applied at the rate of 20 pounds peracre to soil previously planted with said plant species.

We claim:

1. A neutral ester of a polyhydroxyphenol and apolychloro-monocarboxylic acid wherein the acid is selected from thegroup consisting of the 0:,oc-diChlOIO-3liPhfltiC acids andu,a,;8-trichloro-aliphatic acids containing from 3 to 5 carbon atoms,inclusive, and trichloroacetic acid.

2. Resorcinol bis- (a,a-dichloropropionate).

3. Tetrachlorohydroquinone bis-(a,a-dichloropropiomate).

4. Pyrocatcchol bis-((1,0:,fl-trichloropropionate).

5. Pyrocatechol bis-(a,u-dichloropropionatc).

6. 3,6-dichloro-1,2,4,5-benzenetetrol tetra-(u,a-dichloropropionate).

No references cited.

1. A NEUTRAL ESTER OF A POLYHYDROXYPHENOL AND APOLYCHLORO-MONOCARBOXYLIC ACID WHEREIN THE ACID IS SELECTED FROM THEGROUP CONSISTING OF THE A,A-DICHLORO-ALIPHATIC ACIDS ANDA,AP-TRICHLORO-ALIPHATIC ACIDS CONTAINING FROM 3 TO 5 CARBON ATOMSINCLUSIVE, AND TRICHLOROACETIC ACID.